Fuze



` H. BURR! ETAL Feb. 25,1957

FUZE

2 She'ets-Sheet 1 Filed July 5, 1952.

9 INVENTQILS;

ATTOKNESL Feb. 26, 1957 H. BURR! ETAL FUZE 2 Sheets-Sheet 2 Filed July5, 1952 United States FUZE Heinrich Burri and Fritz Alfred Schori,Zurich, Switzerland, assignors to Machine Tool Works Oerlikon,Administration Company, Zurich-Oerlikon, Switzerland, a Swiss companyApplication `Iuly 3, V1.952, Serial No. 297,136 2 Claims. (Cl. 102--71)The present invention relates to a fuze with a built-in self-destructiondevice, in which fuze the detonator containing the priming charge is sodisposed in the transport position that it is unable to ignite theintensifying charge. This arrangement has the advantage thatself-ignitionrof the priming charge, such as may occasionally occur instorage, or in the gun barrel when tiring, willfnot be transmitted tothe high-explosive charge of the shell.

The fuze in accordance with the invention consists of a casing, aspring-loaded percussion pin or striker mountedl therein forlongitudinal displacement and carrying two flyweights arranged onswivelling arms and ableV to bear against an oblique surface of thecasing underthe iniluence of centrifugal force, an intensifying oramplifying charge arranged at thel rear end of the casing, and 'a memberdisposed between the percussion pin or vstriker and the intensifyingcharge and capableof rotation about an axis perpendicular to the axis ofthe striker, said member having a bore containing a detonator which canbe rotated into the path of the striker and which, in this position,communicates with the intensifying charge through a bore in the casing,and said fuze is ch'aracterized by the fact that the rotatable member isprovided' with a recess or cavity against which the striker abuts in thetransport position in such a`wayfthat`th'e striker locks the memberbefore and during'iring, in a position in which the detonator isswivelled' out of the path of thestriker and in which also theborebetween the rotatable member and the intensifying charge is closedby the said member.

In the: accompanying drawing, several embodimentsof the fuze inaccordance with the invention are depicted. In the drawing: y

Figure 1 is a longitudinal sectional Vview of'a first ernbodiment of thefuze; in transport position;

4 Figure 2 is a longitudinal sectional view of the fuze in transportposition, taken `along 'the line I-I inFigure l;

FigureV 3 is a longitudinal sectional view of -the fuze-in the armedcondition;

Figure 4 is a longitudinal sectional view of the fuze in the detonatingposition; e

Figure 5 is a fragmentary sectionalview of thefuze in a secondembodiment, in transport position;

Figure 6 is a fragmentary sectional view of :the 'second embodiment inthe armed condition;

Figure 7 is a longitudinal sectional view of a further embodiment of thefuze;

Figure 8 is a longitudinal sectional view of a further embodiment of thefuze.

In the embodiment depicted in Figures 1 to 4, the numeral 1 designatesthe fuze casing, which is screwed on to the body of the projectile andis closed at its forward end by a plate 5. Disposed in the longitudinalaxis of the fuze is the percussion pin o'r striker 2 to which theswivellingl arms 3 with the roller-shaped ilyweights 4 are attached. Thestriker 2 is acted upon by the spring 6. The latter abuts at one endagainst a shoulder of the the spring 6 that the striker pin abutsagainst the plate 5 2,782.3 7 Patented Feb. 26, 1957 fuze: casing-f1 andat the other end through a bushing 7 againstfa ycollar 2a of the striker2, and tends to force the-striker Vto the rear.

The lmovement of the striker to the rear isprevented in the itransportposition by the spherical member 8, which `is disposed in a sphericalmount or socket constituted by the .parts 9 and 10. The spherical member8 Ais provided,.on an axis perpendicular to the axis of the fuze,1withtwo cylindrical trunnions'or journals 11 which are guided ina slot 9a ofthe part 9. The 4spherical member` 8 is -thereforerotatable only aboutthe said axis. Disposed in a bore in the member 8 is the detonator 12.In thel transport position the member 8 is so rotated that the'striker2cannot pierce the detonator 12. In this position, the shoulder 2b ofthe striker is forced by the spring 6 against the flattened area8a`ofthe surface of the member 8, thereby preventing therlatter fromrotating;-

Whenthe projectile is-red, the yweightsbear against an: oblique surface10a of the member 10 and, by one component of their centrifugal force,draw the striker forward against-the pressure oflthe spring 6. As aresult, the striker or percussion pin is lifted from the at-StVonthemember'S and the latter rotates under the actionofthecentrifugal forces until its bore lies coaxial with the striker pin2. t In this position the member 8-is held by the ball 13, which,accommodated in the short bore-8b, emerges into the recess 9b of part9'on' the rotation of the member Sand` abuts against the lower edge ofthep'art' 101 In thisarmed position, shown in Figure 3, the strikerisf'able to pierce the detonator, the detonation of which istransmitted'by the intensifying charge 14 -to the high'- explosivecharge of the projectile.

The'spherical member 8 has a certain amountfof play in Iits mountorbearing so that it can perform a short movement in the axial directionof the fuze. The length ofthe `slot 9a in this latter direction is soproportioned thatthe member- 8, in its rearmost position, lies flushagainstthe bearing surface by its entiresurface, whilst the journals ortrunnions 11 have a clearance in the axial direct-ion of the fuze in theslot 9a. In the forward position -of-the member 8, the trunnions 11 abutagainst the under edge of the member 10, whilst the surface ofthe memberS in not in contact with the surface' of the spherical socket.

The following is the manner in which the fuz'efuncti'onsz` -In'thetransport' position (Figure 1), the spherical member 8 is `so turnedthat the striker 2 cannot pierce thdeton'ator 12 and vat the saine timethe communication between the detonator 12 and the intensifying charge14 is blocked.l This blockage has the result thatin the event ofls'pontaneousignition of the primer composition ofthe detonator'lZduring storage or duringV transport, the intensifyingcharge 14 is notdetonated. The rotor 8 is held in'lthe'transport position by the striker2, the latter being forced Vagainst the at 3a by the pressure of thespring-A.-

When the projectile is fired, its acceleration forces Vthe striker pin 2and the spherical member 8 to the rear. As a result, the striker ispressed rmly against the flat 8a of the body 8. Moreover, the frictionof member 8, which member is firmly pressed by the acceleration forceinto the spherical socket, opposes the rotation of said member. Onlywhen the projectile has left the gun barrel do the flyweights 10a, whichbear against the oblique surface 10a, draw the striker pin, by acomponent of their centrifugal force, so far forward against thepressure of As a result, the member 8 is liberated and rotates under theaction of the centrifugal force until the ball 13 disposed in the bore8b, which ball 13 is likewise caused by the centrifugal force to slideoutwards into the recess 9b of the member 9, encounters the under edgeof the member 1l). In this position the bore of the member 8 is coaxialwith the striker pin and the communicating bore to the intensifyingcharge is liberated. The fuze is now armed (Figure 3). This arming ofthe fuze cannot occur until the projectile has emerged from the gunbarrel.

Owing to the friction of the air, the rotary speed of the projectileprogressively diminishes. As a result, the centrifugal force of theilyweights becomes steadily less until the moment finally arriveswhenthe axial component of the centrifugal force becomes smaller thanthe force of the spring 6, whereupon the yweights 4 slide off thesurface a and the striker pin 2 is driven by the spring 6 into thedetonator and provokes self-destruction of the shell (Figure 4). If theprojectile strikes a target, the forward part of the fuze is compressedand the striker pin 2 is driven into the detonator 12.

In the embodiment shown in Figures 5 and 6 the fuze is not armed untilthe projectile has travelled a certain distance after leaving the muzzleof the gun. To achieve this end, the plate 5 of the embodimentpreviously described is replaced by a rolled-in plate 15. In a cavity ain the plate 15 is a compound 16Ymelting at low temperatures, forexample at temperatures below 150 centigrade. The striker pin 2 abutsfirmly against the cornpound 16 through a hole 15b in the plate 15 andcannot be drawn forward by the yweights so long as the com- -pound 16isin position.

The manner in which the device functions is as follows:

As in the embodiment previously described, when the projectile is redthe striker pin Z and the spherical member 8 are forced to the rear bythe forcesV of acceleration, with the result that the member 8 cannotrotate. When `the projectile has left the gun barrel, the flyweightstend to draw the striker pin forward by one component of theircentrifugal force, and thereby to accomplish the liberation of thespherical member. The striker pin 2, however, bears by its forward partagainst the compound 16 and is thereby prevented from performing such amovement. When acertain time has elapsed, the compound 16, which is madeof material of low melting point, melts. The striker pin can now moveforward and reach its armed position in accordance with Figure 3,whereby the spherical member S is liberated. For the rest, the functionof therfuze is the same as described in reference to the precedingembodiment.

In the embodiment shown in Figure 7, the rotatable member, designatedbythe numeral 17, has no trunnions, but rises solely under the influenceof its centrifugal force. The strikerpinZ blocks the rotatable member 17by engaging, by its shoulder 26, in a cylindrical depression 17a intherotary'member 17. As a result, when the projectile fis tired therotatable member 17 cannot rotate and arm., the fuze until the yweights4 have drawn the striker pin.2 forward byV one component of theircentrifugal force. If, owing to erosion ofthe gun barrel, the rotaryspeed at which self-destruction occurs is not achieved when theprojectile is fired, the fuze remains unarmed. For the rest, the mannerin which the fuze functions is the same as described in reference to thepreceding embodiments.v

It is also possible to make the depression 17a with tapered sides, inwhich event, by suitably selecting the angle of taper of the wall of thetapered depression, the arming response limit can be fixed as desired.

In the embodiment shown in Figure 8, the rotatable member 17 has twoshort, coaxially aligned bores 17b located in the pivotal axis of themember 17. Accommodated in the bore 17b are balls 18 which, after thefiring of the projectile, move outwards under the action of thecentrifugal force, bear against the surface 9d, and thereby serve asbearings for the body 17 during its rotation.

The embodiments described are, needless to say, only a few of numerouspossibilities of implementing the inventive idea. Y

What we claim is:

l. In a projectile, a casing having a passage formed therein andextending from front to rear along a longitudinal axis, a rotor pivotedin said casingb'ehind said passage for rotation about a transverse axisextending at right angles to said longitudinal axis, said rotor beingrotated about said transverse axis by centrifugal forces produced whensaid projectile is rotated about said longitudinal axis, a striker pinmovably mounted in said passage, resilient means located in said casingand engaging saidtstriker pin to hold it in engagement with said rotorin the transport position andy thereby secure the rotor againstrotation, pin-retaining means located in front of said casing andcomprising a compound closing the front of said passage and melting byheat developed by the `firing of the projectile, said pin-retainingmeans preventing the pin from shifting out of its transport positionprior to firing, and means actuated by centrifugal forces and connectedwith said striker pin for moving said striker pin out of engagement withsaid rotor when the projectile is rotated about the longitudinal axisand after the melting of said compound, said pin-retaining means furthercomprising anabutting surface for the striker pin to prevent the strikerpin from moving beyond the armed position after the melting of thecompound.

2. A projectile in accordance with claim l, wherein said casingcomprises a seat at the rear of said passage, whereby a rotation of saidrotor is normally prevented by frictional engagement of said rotor withsaid seat, said casing further having formed therein slots extending onopposite sides of said rotor, and journals connected with said rotor andextending in the direction of said transverse axis, said journalsprojecting into said slots and forming with said slots bearings forholding the rotor with play 'in the direction of said longitudinal axis.

References Cited in the tile of this patent UNITED STATES PATENTS1,774,043

